Hostscan bediseasedfromlatencycondition by thedecreasingofhost's immunity and stimulationof condition, and soon , thenbecome a carrierandinfectioussource.
Immunity to dengue is low in Singapore's population because ofthe intensive dengue-carrier controls, "making the population vulnerable to outbreaks, " said Ng Lee Ching, director ofthe Environmental Health Institute at Singapore's National Environment Agency.